docs: def _max_form(f, colname):
          """
          Assumes dataframe with hierarchical columns with first index equal to the
          use and second index equal to the attribute.
  
          e.g. f.columns equal to::
  
              mixedoffice   building_cost
                            building_revenue
                            building_size
                            max_profit
                            max_profit_far
                            total_cost
              industrial    building_cost
                            building_revenue
                            building_size
                            max_profit
                            max_profit_far
                            total_cost
          """
          df = f.stack(level=0)[[colname]].stack().unstack(level=1).reset_index(level=1, drop=True)
          return df.idxmax(axis=1)